[ClusterLabs] Antw: [EXT] resource cloned group colocations

[Ulrich Windl]

>>> Gerald Vogt <vogt at spamcop.net> schrieb am 02.03.2023 um 08:41 in Nachricht
<624d0b70-5983-4d21-6777-55be91688bbe at spamcop.net>:
> Hi,
> 
> I am setting up a mail relay cluster which main purpose is to maintain 
> the service ips via IPaddr2 and move them between cluster nodes when 
> necessary.
> 
> The service ips should only be active on nodes which are running all 
> necessary mail (systemd) services.
> 
> So I have set up a resource for each of those services, put them into a 
> group in order they should start, cloned the group as they are normally 
> supposed to run on the nodes at all times.
> 
> Then I added an order constraint
>    start mail-services-clone then start mail1-ip
>    start mail-services-clone then start mail2-ip
> 
> and colocations to prefer running the ips on different nodes but only 
> with the clone running:
> 
>    colocation add mail2-ip with mail1-ip -1000
>    colocation ip1 with mail-services-clone
>    colocation ip2 with mail-services-clone
> 
> as well as a location constraint to prefer running the first ip on the 
> first node and the second on the second
> 
>    location ip1 prefers ha1=2000
>    location ip2 prefers ha2=2000
> 
> Now if I stop pacemaker on one of those nodes, e.g. on node ha2, it's 
> fine. ip2 will be moved immediately to ha3. Good.
> 
> However, if pacemaker on ha2 starts up again, it will immediately remove 
> ip2 from ha3 and keep it offline, while the services in the group are 
> starting on ha2. As the services unfortunately take some time to come 
> up, ip2 is offline for more than a minute.

That is because you wanted "ip2 prefers ha2=2000", so if the cluster _can_ run it there, then it will, even if it's running elsewhere.

Maybe explain what you really want.

> 
> It seems the colocations with the clone are already good once the clone 
> group begins to start services and thus allows the ip to be removed from 
> the current node.
> 
> I was wondering how can I define the colocation to be accepted only if 
> all services in the clone have been started? And not once the first 
> service in the clone is starting?
> 
> Thanks,
> 
> Gerald
> 
> 
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